Lumped element y circulator



1967 YOSHIHIRO KONISHI 3,335,374

LUMPED ELEMENT Y CIRCULATOR Filed April 14, 1965 3 Sheets-Sheet 1 I INVENTOR 3 yoslw hi o Kolvfsl'll' ATTORNEYS g- 1967 YOSHIHIRO KONISHI 3,335,374

LUMPED ELEMENT Y GIRCULATOR Filed April 14, 1965 3 Sheets-Sheet, 2

A (Loss in reverse direction) 4 B (Loss in fim/ard d/FECt/OIL) 2- J A W I? F T I I44 I46 I43 I50 I52 I 54 I56 Rasonance absorbtion ,06'6 J r F? -7 ATTORNEY;

United States Patent LUMPED ELEMENT Y CIRCULATOR Yoshihiro Konishi, Kawasaki, Japan, assignor to Japan Broadcasting Corporation, Tokyo, Japan Filed Apr. 14, 1965, Ser. No. 448,069 Claims priority, application Japan, May 14, 1964, 39/215,899 6 Claims. (Cl. 333-11) The present invention relates to a lumped element Y circulator and more particularly to the arrangement of conductors for VHF or UHF circulator circuit element with ferrite bodies. The ordinary Y stripline circulator required a certain size in diameter of ferrite bodies to keep their loss characteristics within a certain limit.

It is the object of the present invention to provide a more improved conductor arrangement for a miniat-urized circulator, which can be available to VHF or UHF receivers for the purpose of diminishing a radiation of local oscillator.

According to one aspect of the present invention, a symmetrical Y circulator comprises a plurality of inner conductors which are interposed between ferrirnagnetic bodies, and the inner conductors are arranged rotationally about a symmetrical axis of an outer conductor frame, and consist of groups of parallel conductors having at least two parallel conductors, which are led from each terminal port of the outer conductor frame. Each conductor intersects with the conductors of the other groups with cross angle of 120, and they form distributed points of insulated intersection on the surface of the ferrimagnetic bodies, one end of each parallel conductor is connected to a condenser which is grounded at each terminal port, and the other end is connected to the outer conductor at the opposite position of each terminal port.

This arrangement of conductors makes a uniform distribution of the high frequency magnetic field, and effectively contributes to make a circular rotating field inside of ferrimagnetic bodies corresponding to a rotating excitation at each terminal, which is required to realize a circulator. This results in making a wide band circulator and making it possible to adjust the center frequency of lumped element Y circulator only by changing the capacitance of the condensers connected at each terminal port.

According to the second aspect of the invention in a symmetrical Y circulator, inner conductors are interposed between ferrimagnetic bodies and arranged symmetrically about the center axis of outer conductor frame, at least two parallel conductors led from each terminal port on the outer conductor frame intersect with an angle of 120 each other forming distributed points of insulated intersection, by inserting thin sheet of insulating material between the layers of said parallel conductors led from different terminals, and connecting the matching resistor to one port, an isolator is realized. Its center frequency in the backward direction can be adjusted by changing the capacity of condenser at the terminal port where the resistor is connected, and the center frequency in the forward direction can be adjusted by the capacity of condensers connected to the other ports, i.e. the input and output terminal ports.

According to the third aspect of the present invention, variable condensers are connected to each inner conductor at each terminal port so that center frequency of the circulator can be widely adjusted in a wide frequency band only by changing the capacity of condensers, while keeping the same structure of the inner conductor mesh, the same ferrimagnetic bodies and keeping the same intensity of the external magnetic field applied.

In order that the invention may be fully understood ice and readily carried into effect, it will now be described with reference to the accompanying drawings, of which:

FIGS. l-a and H) represent diagrammatic crosssectional view and front view of an ordinary Y circulator respectively;

FIGS. 2 and 3 are explanatory views which show polarization and the propagation of waves in the high frequency magnetic field of a Y circulator; 1

FIGS. 4-a and 4-17 represent diagrammatically a layout for the components of a circuit in the Y circulator according to the invention in plan view and front view respectively;

FIG. 5 is a characteristic curve of a lumped element Y circulator according to the invention;

FIG. 6 is circular polarized permeabilities in positive and negative directions in ferrimagnetic material excited by D.C. magnetic field;

FIG. 7 illustrates the eigenvalues of the lumped element Y circulator of the invention;

FIGS. 8a, 8-b and 8c are equivalent circuits of the eigenvalues for the Y circulator of the invention;

FIG. 9 is an explanatory diagram indicating the adjustment of the eigenvalues by condensers at each terminal port; I

FIG. 10 is a performance data of a lumped element Y circulator at various frequencies corresponding to the variable condenser range of the Y circulator of the invention; i

FIGS. ll-a and 11h represent an equivalency between eigenvalues of rotationally symmetrical 3-port circuit such as circulator and equivalent one port circuit as to eigenvalues corresponding to rotating field; and

FIG. 12 is an equivalent circuit diagram of lumped element Y circulator when considering its frequency characteristics.

In the present invention, Y circulator (three-terminal non-reciprocal circulating circuit) utilizes the phenomena that ferrite (ferrimagnetic material) presents an asymmetric anisotropic tensor permeability in the microwave band, and is miniaturized by forming lumped element circuit.

The ordinary symmetrical Y strip circulator has a construction as shown in FIGS. l-a and l-b. The inner conductors 1 which are interposed between two ferrite bodies 2 and 2, are enclosed in an outer conductor?) with the terminal ports 3a, 3b and 3c, and D.C. magnetic field H is applied normal to the surface of the ferrite bodies.

The conceptional explanation of the performance of Y circulator referring to FIGS. 1-11, 1-12, 2 and 3, is described as follows:

As applying high frequency waves to the terminal port 3a, the high frequency magnetic field having components parallel to the surface of the drawings is induced (as shown by a row of arrows in FIG. 2), and propagates inward along the dotted line and gradually turning the direction as indicated by the arrows. If it is properly designed, the wave applied to terminal port 3a appears at terminal port 3b, but not at terminal port 3c. This is due to the fact that the permeability of ferrite takes the different values by the direction of a rotating magnetic field around the applied D.C. magnetic field.

Usually, right hand screw rotation (clockwise) against D.C. magnetic field is called as positive and left hand rotation as negative and corresponding permeability is nominated positive or negative permeability of circular polarized wave and represented by M and ,u, respectively.

If the D.C. field intensity is varied, ,u and ,u. will vary as shown in FIG. 6.

As the D.C. field excitation is increased starting from O, the permeability o, changes from positive to negative at a certain point of excitation, and D.C. field strength 'field excitation for diminishing the loss caused by magnetic material.

As illustrated in FIG. 6, in such operation range, positive permeability n+ is larger than negative permeability IL;

Now considering linear polarized waves coming into terminal port 3a and divided into two components, of which rotating field against D.C. field direction as right hand and left hand screw, the former is equivalent to positive rotating field and the latter is negative rotating field. When the DO field is larger than the resonance field, the permeability of positive rotating field is larger than that of negative rotating field, i.e., p. ,u accordingly, the propagation velocity of former is slower than that of the latter. The rotating velocity of field, which is determined by frequency, however, is also independent of positive or negative. Therefore, the propagating direction of the high frequency is twisted to the right at a position of some distance advanced inwardly from terminal port 3a.

Thus, in order to obtain such a circulator, it is nece sary to keep a certain difference between ,u. and ,u. whic cause the polarization of waves.

Three terminal ports of such circulator are excitated simultaneously, by high frequency voltage with equal amplitude but different phase.

In the first method of excitation the three terminal ports are excited simultaneously by in-phase voltage, which is termed first eigenvector. The second method of excitation, which is called second eigenvector, is to excite the terminal port 3b by a voltage of which phase angle leading 240 to that of terminal port 3a, and simultaneously to excite the terminal port 30 of which phase angle leading 120 to that of terminal port 3a. The last case of excitation is called third eigenvector of which terminal port 312 leads 120 and terminal port 3c leads 240 to terminal port 3a.

In any case of eigenvector, applying excitation to terminal ports 3a, 3b and 3c simultaneously, they cause reflection of wave on the terminal ports, having equal value of reflection coefficient. These reflection coeflicients are called as eigenvalue. Thus a Y circulator has three different eigenvalues for the first, second and third eigenvector.

The circulator can be operated when the eigenvalues and the eigenvectors of the three terminal ports are kept in such special relations between them as shown in Table 1.

When plotting Table l on the S-miths Chart, it can be seen that the three eigenvectors are kept in same intervals of the angle 120. For example, assuming the first eigen- 4 value S which is in-phase exciting, be -l, it comes to the position, as shown in FIG. 7, where corresponding to infinite admittance on the Smiths Chart, and admittanccs of the other eigenvalues take their position on In such a circulator, if it is desired to make the insertion loss as small as possible, the eigenvalues should take their positions as shown in FIG. 7. In the shown positions the admittances of second and third eigenvalues take small values. Thus it is possible to make the high frequency magnetic field in the ferrimagnetic body stronger in the central part and weaker in the periphery. In other words it may be said that for the second and third eigenvectors which excite the magnetic material by negative and positive rotating fields, the high frequency rotating magnetic field becomes stronger in the central part, and the magnetic energy concentrates in the central part of the magnetic material. The peripheral part of the body will effect only to contribute a better rotating field in the central part.

On the other hand, the reason of making the difference between the second and third eigenvalues, as described above, is due to the differenceof the magnetic energy of the central part, and thus due to the difference of ,U.+ and ,u

Thus by the known construction of Y stripline circulator, in case of a low insertion loss is required, the magnetic bodies should be made in a suitable dimension, which satisfies the above mentioned eigenvalues, and there is an optimum value for the dimension. However, under such conditions the lower the frequency the larger the diameter is required. This may also be understood from the fact that the twisting amount of high frequency field is inversely proportional to its frequency.

The inventor had developed a Y circulator with reduced dimension for VHF or UHF band, which may be applied to weak power transmission and available in the receiving devices, by making many holes through the magnetic bodies which are placed on both sides of the inner conductors and inserting dielectric materials in the holes to increase capacitive effect, and to produce a large twisting angle of waves, i.e. Faradays rotation to make equivalent effect as the magnetic material bodies.

The object of the invention is to provide more miniaturized Y circulator suitable for very weak power.

In the above described ordinary Y circulator of known construction, the magnetic energy of rotating magnetic field concentrates at the central part of magnetic material and less in periphery. This invention is based on the consideration that, when exciting a magnetic body by the eigenvectors which induce the rotating field, i.e., by the second and third eigenvectors, if it is possible to induce the rotating magnetic field uniformly in all parts of the magnetic body, the very efiicient performance of magnetic body can be obtained, and thus minimize its dimensions. To realize such effect, when exciting the magnetic body by second and third eigenvectors from a constant current source (hereinafter referred to rotating eigenvector), as large high frequency magnetic energy must be induced in the magnetic body as possible, and in this case, any static energy needs not to exist. Moreover the high frequency magnetic energies thus induced are desirable to have as much difference as possible in the sense of positive and negative rotating vectors, therefore the high frequency magnetic field in the magnetic body must be a perfect circular rotating magnetic field.

To this end, symmetrical Y circulator according to the invention, comprises inner conductors 1 interposed between two plates of rotationally symmetrical shape (such as disc shaped plates) of ferrirnagnetic material bodies 2, 2' and the outside of thus constructed body is held in an outer conductor frame 3 as shown in FIGS. 4-a and 4-b.

FIG. 4-a shows an inside construction of a circulator according to the invention. At least two conductors are connected to corresponding terminal port of the circulator, and these conductors are arranged to form a mesh as shown in the figure. Each group of conductors led from each terminal port are insulated from each other. This mesh is composed to induce a uniform rotating field inside the magnetic body. For example, as shown in FIG. 4-a, two narrow conductor strips a, (1" led from terminal port 3a, b, b" from terminal port 3b, and c, c" from terminal port 30, are arranged in rotationally symmetrical state so as to keep 120 each other. In this case, if arranging the conductors, b, b" over the conductors a, a" and arranging the conductors c, 0" over conductors b, b", the rotational symmetricity will be lost. Therefore the conductors are woven to form a mesh, in the order of a, b, c, a", b", 0'', while keeping the insulation each other. One end of each inner conductor is grounded through one of condensers C C and C for adjusting each eigenvalue and the other end of each conductor is connected to the opposite side of the outer conductor frame 3. Each group of conductors may preferably be short circuited at the opposite side of each terminal port and connected to the outer conductor frame at the proximity of the periphery of said magnetic bodies as shown by dotted line s in FIG. 4a. The side elevation is shown in FIG. 4-b, it is seen that a plurality of conductors 1 are interposed between two plates of magnetic materials 2, 2' and DC. magnetic field H is applied normal to the magnetic bodies.

The operation of the invention will now be described referring to the above embodiment.

Consider now a case incoming wave is incident at the terminal port 3a and transmitted from terminal port 30, and if there is no D.C. field applied (H =0), both the high frequency field H and flux density B have vertical directions to the conductors connected to 3a, and have equal coupling to the conductors of 3b and 30, therefore, the incoming wave is equally separated and transmitted to terminals 3b and 30.

If D.C. field is gradually increased, the directions of high frequency field H and flux density B will be shifted to the clockwise direction against the direction of D.C. field, and H changes from linear polarized wave to negative elliptical polarized wave, while B is kept linearly polarized wave. Finally, at the suitable D.C. field strength, the flux density B takes its direction exactly parallel to the conductors which are connected to the terminal 3b.

Such conditions depend upon the configuration and dimension of the mesh, characteristics and dimension of the magnetic bodies, and capacitance value of the condensers connected to each terminal port.

The several embodiments of the invention will be described in the following:

(1) If the backward band width A and center frequency f are given, there can be obtained the value 1 by Equation 1 which relates to /L+ and ,u. of the working point on FIG. 6.

6 (2) Capacitance of condensers to be connected to each terminal port may be obtained by the Equation 2.

(3) The value of '21 required for the specified band width W is obtained by Equation 1. As 1 is related to M and ,u in FIG. 6, the value of e, which is an eigen-inductance of the conductor mesh without ferrimagnetic bodies, is obtained by Equation 3.

2 u- The permeability characteristic curve in FIG. 6 may be Ms is saturated magnetization, r is gyromagnetic ratio, H is internal D.C. magnetic field in the ferrite.

(4) As 6 and dimensions of mesh part are previously determined by measurement, by calculating the necessary value of e by item 3), the dimensions can be determined.

(5) Assuming that the insertion loss of circulator thus constructed may be L(dB). This may be calculated by Equation 5.

Al as; an; wcfict 11 1 +Q- n where QJ is the quality factor of permeability in positive circularly polarized Wave.

Q is the quality factor of permeability in negative circularly polarized wave.

Q is the quality factor of capacitance connected to each terminal port.

The explanation of Y circulator of the invention in the view point of eigenvalue is as follows:

Now, referring to FIG. 4-1:, when every terminal ports are excited by in-phase Waves with same amplitude, there induces no field at the cross points P of the conductors which are insulated and arranged with angle each other and having in-phase current. Therefore, no magnetic energy exists in the magnetic bodies. Since said other ends of conductors are all short circuited, the input ports S S and S will also become short circuited state as if they are closed. Considering one terminal port of such condition, it corresponds to two-terminal impedance which is a short circuit as shown in FIG. 8-a. This condition corresponds to infinite admittance on Smiths Chart (Y=eo) as shown in FIG 9.

When excited with second eigenvector, there induce counter clockwise rotating field in the magnetic bodies. In this step, adding external D.C. field, normal to the face of the magnetic bodies as shown in FIGS. 4-a and 4-b. It will act for these rotating field with permeability of r (called negative circular polarized Wave permeability). In this invention, at each cross point P in FIG. 4a a rotating field is induced and gives negative circular polarized permeability in almost all parts of the material. In the invention, it may be considered that the static energy stored in the discs being equal to zero, because the dimension of the magnetic bodies is small and the conductors are short circuited at opposite ends. Therefore, equivalent circuit of eigenvalue in this case presents an inductive value Ir, and considering with capacitance C connected to each terminal port, it makes a parallel resonant circuit as shown in FIG. 8b.

Now, the reason why the circuit presents equivalent inductance may be explained as follows:

When a Y circulator is excited by the second eigenvector, the permeability in almost all parts of the magnetic material becomes r. So as to the second eigenvalue, the ferrimagnetic bodies may be replaced by isotropic bodies which have the same permeability as r. However, the part of this isotropic bodies takes the same eigenvalue for the third eigenvector because of its rotational symmetry. Then, a new vector b composed by linear combination of the second and third eigenvector is introduced as follows:

The new eigenvector b also takes the same eigenvalue as that of the second eigenvector as to the isotropic bodies.

Now, exciting with the new vector b there is formed a magnetic wall in the central part of the circuit as shown in FIG. 1la, and the circuit takes the same eigenvalue as that of the equivalent two-terminal impedance as shown in FIG. ll-b, which takes the second eigenvalue. Therefore, the admittance at the terminal port 3a for the second egienvector is the same one as the admittance at terminal port 3a, where the ferrimagnetic material at the central part of mesh conductors is replaced by isotropic material and the conductors are short cir-cuited along the conductors connected to terminal port 3b. That is the reason why the circuit is inductive.

In the same manner as described above, in the case of excitation by third eigenvector, the circuit can be considered as an equivalent circuit as shown in FIG. 8c, and the ferrimagnetic bodies acts with different permeability M and present inductance L Representing eigenvalues for L and L on Smiths Chart, these eigenvalues are at the positions of dotted arrows as shown in FIG. 9. By capacitance C of the parallel condensers C C C the positions of these eigenvalues rotate clockwise and come to the positions as shown in full line arrows in FIG. 9.

If the three eigenvalues, thus formed, are in the positions separated in an angle of 120 from each other, the circulator is realized.

Comparing the invented Y circulator with an ordinary Y stripline circulator which has the same size of ferrimagnetic disks, the Y circulator according to the invention presents excellent advantages in band width characteristics and less insertion loss, than the known type. Following description explains the reason of such effects.

In the known construction of Y is circulator as shown in FIG. 1, the eigenvalues in ferrimagnetic bodies are also same as equivalent inductances. However, when excited with second and third eigenvectors, the generation of circularly rotating field is limited only in a small part around the center of the discs, and in the other part an elipsoidally rotating field is induced, and thus make only a. little contribution for the difference between L and L'+. On the other hand, to make the phase difference between second and third eigenvalues as 120, it is required to make certain amount of difference in admittance of L- and L'+. Therefore the values L'- and L+ must be reduced to smaller values to satisfy the required difference between their admittances It results in requiring the condensers to take much larger value than the value of C, for adjusting the position of eigenvalues at full line arrows shown in FIG. 9. Consequently, referring to FIG. 8, it is required larger capacitance than C of FIGS. 8-17 and 8-c, and also smaller inductances L- and L'+ than L and L On the other hand, it can be proved that the frequency characteristics of the circulator is proportional to the sum of the whole reactive energy (electrostatic energy +magnetic energy) of second and third eigenvalues when excited at each terminal by constant voltage eigenvector. However, the whole reactive energy becomes larger accordingly as capacitance C becomes larger and the L becomes smaller. By the construction according to the present invention it can be obtained a much small value of the whole reactive energy than that as shown in FIG. 1, and it presents a Wider band width characteristics.

Next, in the consideration of insertion loss, as the loss term is represented by products of whole reactive energy and loss angle, by the invention which represents minimum reactive energy, a small insertion loss can be attained.

The experimental data of the embodiment of the invention shows its characteristics diagram as shown in FIG. 5.

Further consideration concerning an aspect, the embodirnent of the invention, is given in the following:

The three condensers C C and C which are connected to respective inner conductor at each terminal port, can be replaced by variable condensers, thus the circulator may be adjusted to cover a wide frequency range.

For example, it was observed that only varying condensers C C and C under constant external D.C. field, the circulator can be adjusted for use in a wide frequency range as 50 me. to 300 me. FIG. 10 shows the performance data of such circulator.

The explanation for this reason is made as follows:

Now, consider a case being lower frequency. FIG. 6 is a characteristic diagram of positive and negative polarized permeability at a certain frequency under various D.C. field strength, and dotted line shows the reasonance absorption loss. On a different frequency such as further lower frequency, one can get the another performance curve of the permeability, and can also show the operating point in the same field intensity as the former. The latter operating point locates more right on the performance curve corresponding the lower frequency. In other words, when in the case of higher frequency, the D.C. field strength was 0 times the resonance D.C. field, in the case of lower frequency it should take a times, where a' o', because the resonance field increases proportionally to the applied frequency, and on the other hand, the D.C. field is kept in the same strength. That is to say that the lower the frequency the smaller the difference between ,u. and IL Therefore, the difference between L and L+ which causes the difference between second and third eigenadmittance, also decrease. For the admittance is determined by wL wL and reversely proportional to to which act to increase the difference of the adrnitance,

02L wL is kept in constant value regardless to the frequency or. That may be proved quantitatively calculating by Polders equation to apply for value of M and p.

In the circulator described above, the center frequency can be changed in a wide range by varying the value of condensers C C and C which are connected to each terminal port respectively.

In the above description of Y circulator of the invention, it is also possible to connect a compensating capacitor 9 cc as shown by dotted line in FIGURE 4-a between top and bottom inner conductors, and thus compensate the irregularities of rotationally symmetrical arrangement of the inner conductors.

Consider, now, terminating a resistance to one of the terminal ports, for instance, terminal port 3b, the wave incident to terminal port 3a appears on the terminal port 3c, but wave into 30 does not appear on 3a, for the wave is absorbed by the terminating resistance. Therefore, under observation on the view point referring to Sc and So, this may be said as an isolator. In this isolator, certain frequency range of wave is not transmitted from terminal port 30 to 3a, but in shifted frequencies out of the range generally it appears on terminal port 3a. This frequency range is determined by capacitance C of terminal port 3b. On the other hand, wave coming into 3a is transmitted to 30 without loss in some frequency range but generally gives loss for the frequency out of the range. The lossless frequency band may be transferred by adjusting condensers C and C which are connected to terminal ports 3a and 30 respectively. Thus, the center frequency in the forward direction of 3a, 30 can be ad justed by condensers C and C which are connected to terminal ports 3a and 3c, and the center frequency in the backward direction can be adjusted by condenser C2 at terminal port 3b. In that way, the center frequency can be transferred arbitrarily in either direction of forward or backward as an isolator.

Further for the sake of completeness, in lumped element Y circulator of the invention, because of internal magnetic energy W and electrical energy W are stored in the state of complete separation (W is in the conductor mesh, and W is in the condenser added externally), the equivalent circuit representing the frequency characteristics is as shown in FIG. 12 and it can be expressed by ideal circulator (which band width is infinite and operates as circulator at any frequency) and parallel resonance circuit (its center frequency is equal to the center frequency of the circulator, and parallel condenser C has a capacitance which is equal to that of the condenser terminated to the terminals of the circulator).

Further, by externally connecting a suitable pure reactive four-terminal network to the Y circulator, the frequency band width can be increased easily and the network can be more easily and more exactly synthesized than the ordinary stripline circulator because of the separateness between magnetic and electric energies in-v side the lumped element circulator.

What I claim is:

1. Lumped element Y circulator which comprises a plurality of inner conductors, a pair of ferrimagnetic bodies, an outer conductor frame in which the inner conductors comprising three groups of parallel conductors are arranged in rotational symmetry about center axis of the outer conductor frame, each group of inner conductors having at least two parallel conductors leading from each terminal port of the outer conductor frame, said inner conductors being connected to ground through a condenser at each terminal port, at least one of the other ends of said inner conductors of each group being connected to the outer conductor frame at the opposite side, said inner conductors crossing with the inner conductors in the other groups at an angle of said inner conductors being insulated from each other at the crossing points, and the groups of said inner conductors being interposed between said magnetic bodies, to form a lumped element circuit by uniformly distributing said points of insulated intersections among the surface of the said magnetic bodies and that the amount of permeability of said magnetic bodies can be uniformly distributed inside said magnetic bodies.

2. Lumped element Y circulator applicable to an isolator according to claim 1, wherein a thin sheet of high frequency insulating material is inserted between each group of the inner conductors thus forming an interposed layer of the group of conductors and the thin insulating sheet, and a resistor is connected to one of the inner conductors at a terminal port, so that the center frequency in the reverse direction can be adjusted by the condenser of the inner conductor to which said resister is connected, and the center frequency in the forward direction can be adjusted by the capacity of the condensers of the inner conductors of the other groups, i.e. by the condensers at the input and output terminal ports.

3. Lumped element Y circulator according to claim 1, wherein a variable condenser is connected to each inner conductor at each terminal port so that the center frequency of the circulator may be widely adjustable over a wide frequency band, While keeping the same structure of the inner conductor mesh and using the same magnetic bodies and also keeping same intensity of the external magnetic field applied.

4. Lumped element Y circulator according to claim 1, wherein each group of said inner conductors is connected to ground through at least a condenser at each terminal port, and the other ends of said inner conductors of a group are short circuited and connected to the outer conductor frame at the proximity of the periphery of said magnetic bodies.

5. Lumped element Y circulator according to claim 1, wherein a compensating capacitor is connected between top and bottom of inner conductors of the arrangement, and thus to compenesate for the irregularities of the rotationally symmetrical arrangement of the inner conductors.

6. Lumped element Y circulator according to claim 1, wherein the three groups of inner conductors form a mesh arranged symmetrically with the co-axial centers of the ferromagnetic bodies.

References Cited UNITED STATES PATENTS 3,226,659 12/1965 Stracca 333-1.1 3,246,261 4/1966 Stelzer 333-1.1

HERMAN KARL SAALBACH, Primary Examiner. M. NUSSBAUM, Assistant Examiner. 

1. LUMPED ELEMENT Y CIRCULATOR WHICH COMPRISES A PLURALITY OF INNER CONDUCTORS, A PAIR OF FERRIMAGNETIC BODIES, AN OUTER CONDUCTOR FRAME IN WHICH THE INNER CONDUCTORS COMPRISING THREE GROUPS OF PARALLEL CONDUCTORS ARE ARRANGED IN ROTATIONAL SYMMETRY ABOUT CENTER AXIS OF THE OUTER CONDUCTOR FRAME, EACH GROUP OF INNER CONDUCTORS HAVING AT LEAST TWO PARALLEL CONDUCTORS LEADING FROM EACH TERMINAL PORT OF THE OUTER CONDUCTOR FRAME, SAID INNER CONDUCTORS BEING CONNECTED TO GROUND THROUGH A CONDENSER AT EACH TERMINAL PORT, AT LEAST ONE OF THE OTHER ENDS OF SAID INNER CONDUCTORS OF EACH GROUP BEING CONNECTED TO THE OUTER CONDUCTOR FRAME AT THE OPPOSITE SIDE, SAID INNER CONDUCTORS CROSSING WITH THE INNER CONDUCTORS IN THE OTHER GROUPS AT AN ANGLE OF 120*, SAID INNER CONDUCTORS BEING INSULATED FROM EACH OTHER AT THE CROSSING POINTS, AND THE GROUPS OF SAID INNER CONDUCTORS BEING INTERPOSED BETWEEN SAID MAGNETIC BODIES, TO FORM A LUMPED ELEMENT CIRCUIT BY UNIFORMLY DISTRIBUTING SAID POINTS OF INSULATED INTERSECTIONS AMONG THE SURFACE OF THE SAID MAGNETIC BODIES AND THAT THE AMOUNT OF PERMEABILITY OF SAID MAGNETIC BODIES CAN BE UNIFORMLY DISTRIBUTED INSIDE SAID MAGNETIC BODIES. 